Cleanup lockmgr interface and exported KPI:

- Remove the "thread" argument from the lockmgr() function as it is
  always curthread now
- Axe lockcount() function as it is no longer used
- Axe LOCKMGR_ASSERT() as it is bogus really and no currently used.
  Hopefully this will be soonly replaced by something suitable for it.
- Remove the prototype for dumplockinfo() as the function is no longer
  present

Addictionally:
- Introduce a KASSERT() in lockstatus() in order to let it accept only
  curthread or NULL as they should only be passed
- Do a little bit of style(9) cleanup on lockmgr.h

KPI results heavilly broken by this change, so manpages and
FreeBSD_version will be modified accordingly by further commits.

Tested by: matteo

4 files changed, 15 insertions, 33 deletions

diff --git a/sys/kern/kern_lock.c b/sys/kern/kern_lock.c
index 5ce5ffd..a13dcc7 100644
--- a/sys/kern/kern_lock.c
+++ b/sys/kern/kern_lock.c
@@ -189,23 +189,18 @@ acquire(struct lock **lkpp, int extflags, int wanted, int *contested, uint64_t *
  * accepted shared locks and shared-to-exclusive upgrades to go away.
  */
 int
-_lockmgr(struct lock *lkp, u_int flags, struct mtx *interlkp, 
-	 struct thread *td, char *file, int line)
+_lockmgr(struct lock *lkp, u_int flags, struct mtx *interlkp, char *file,
+    int line)
 
 {
+	struct thread *td;
 	int error;
 	int extflags, lockflags;
 	int contested = 0;
 	uint64_t waitstart = 0;
 
-	/*
-	 * Lock owner can only be curthread in order to have a deadlock
-	 * free implementation of the primitive.
-	 */
-	KASSERT(td == curthread,
-	    ("lockmgr: owner thread (%p) cannot differ from curthread", td));
-
 	error = 0;
+	td = curthread;
 
 	if ((flags & LK_INTERNAL) == 0)
 		mtx_lock(lkp->lk_interlock);
@@ -576,6 +571,9 @@ lockstatus(lkp, td)
 	int lock_type = 0;
 	int interlocked;
 
+	KASSERT(td == NULL || td == curthread,
+	    ("%s: thread passed argument (%p) is not valid", __func__, td));
+
 	if (!kdb_active) {
 		interlocked = 1;
 		mtx_lock(lkp->lk_interlock);
@@ -594,21 +592,6 @@ lockstatus(lkp, td)
 }
 
 /*
- * Determine the number of holders of a lock.
- */
-int
-lockcount(lkp)
-	struct lock *lkp;
-{
-	int count;
-
-	mtx_lock(lkp->lk_interlock);
-	count = lkp->lk_exclusivecount + lkp->lk_sharecount;
-	mtx_unlock(lkp->lk_interlock);
-	return (count);
-}
-
-/*
  * Determine the number of waiters on a lock.
  */
 int
diff --git a/sys/kern/vfs_default.c b/sys/kern/vfs_default.c
index 26d5640..4648f3a 100644
--- a/sys/kern/vfs_default.c
+++ b/sys/kern/vfs_default.c
@@ -263,8 +263,8 @@ vop_stdlock(ap)
 {
 	struct vnode *vp = ap->a_vp;
 
-	return (_lockmgr(vp->v_vnlock, ap->a_flags, VI_MTX(vp), curthread,
-	     ap->a_file, ap->a_line));
+	return (_lockmgr(vp->v_vnlock, ap->a_flags, VI_MTX(vp), ap->a_file,
+	    ap->a_line));
 }
 
 /* See above. */
@@ -278,8 +278,7 @@ vop_stdunlock(ap)
 {
 	struct vnode *vp = ap->a_vp;
 
-	return (lockmgr(vp->v_vnlock, ap->a_flags | LK_RELEASE, VI_MTX(vp),
-	    curthread));
+	return (lockmgr(vp->v_vnlock, ap->a_flags | LK_RELEASE, VI_MTX(vp)));
 }
 
 /* See above. */
diff --git a/sys/kern/vfs_mount.c b/sys/kern/vfs_mount.c
index 5100f73..146f868 100644
--- a/sys/kern/vfs_mount.c
+++ b/sys/kern/vfs_mount.c
@@ -1239,7 +1239,7 @@ dounmount(mp, flags, td)
 	if (flags & MNT_FORCE)
 		mp->mnt_kern_flag |= MNTK_UNMOUNTF;
 	error = lockmgr(&mp->mnt_lock, LK_DRAIN | LK_INTERLOCK |
-	    ((flags & MNT_FORCE) ? 0 : LK_NOWAIT), MNT_MTX(mp), td);
+	    ((flags & MNT_FORCE) ? 0 : LK_NOWAIT), MNT_MTX(mp));
 	if (error) {
 		MNT_ILOCK(mp);
 		mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_NOINSMNTQ |
@@ -1314,7 +1314,7 @@ dounmount(mp, flags, td)
 		mp->mnt_flag |= async_flag;
 		if ((mp->mnt_flag & MNT_ASYNC) != 0 && mp->mnt_noasync == 0)
 			mp->mnt_kern_flag |= MNTK_ASYNC;
-		lockmgr(&mp->mnt_lock, LK_RELEASE, NULL, td);
+		lockmgr(&mp->mnt_lock, LK_RELEASE, NULL);
 		if (mp->mnt_kern_flag & MNTK_MWAIT)
 			wakeup(mp);
 		MNT_IUNLOCK(mp);
@@ -1330,7 +1330,7 @@ dounmount(mp, flags, td)
 		vput(coveredvp);
 	}
 	vfs_event_signal(NULL, VQ_UNMOUNT, 0);
-	lockmgr(&mp->mnt_lock, LK_RELEASE, NULL, td);
+	lockmgr(&mp->mnt_lock, LK_RELEASE, NULL);
 	vfs_mount_destroy(mp);
 	return (0);
 }
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index 2fe63b0..8095974 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -361,7 +361,7 @@ vfs_busy(struct mount *mp, int flags, struct mtx *interlkp,
 	if (interlkp)
 		mtx_unlock(interlkp);
 	lkflags = LK_SHARED | LK_INTERLOCK;
-	if (lockmgr(&mp->mnt_lock, lkflags, MNT_MTX(mp), td))
+	if (lockmgr(&mp->mnt_lock, lkflags, MNT_MTX(mp)))
 		panic("vfs_busy: unexpected lock failure");
 	return (0);
 }
@@ -373,7 +373,7 @@ void
 vfs_unbusy(struct mount *mp, struct thread *td)
 {
 
-	lockmgr(&mp->mnt_lock, LK_RELEASE, NULL, td);
+	lockmgr(&mp->mnt_lock, LK_RELEASE, NULL);
 	vfs_rel(mp);
 }